1. Field of the Invention
The present invention relates to an on-vehicle electronic device including an antenna circuit such as a preamplifier circuit and interposed between an antenna radiating conductor provided on a glass surface of a vehicle window and an external circuit such as a receiver circuit, and particularly to an on-vehicle electronic device used attached to the glass surface.
2. Description of the Related Art
Conventionally, there has been widely known a method of providing a glass surface of a vehicle window (e.g., a rear window) with a relatively long antenna radiating conductor such as a diversity antenna. Such an antenna device using the vehicle window as the installation space therefor is expected to be increasingly generalized along with the spread of terrestrial digital broadcasting.
As for the signal wave of the terrestrial digital broadcasting or the like, a signal received by the antenna radiating conductor needs to be promptly amplified so that the attenuation of the received signal is suppressed as much as possible to thereby obtain good reception sensitivity. In the antenna device including the antenna radiating conductor disposed on the glass surface of the vehicle window, therefore, an electronic device including therein a circuit board provided with a preamplifier circuit is usually attached to the same glass surface in the vicinity of the antenna radiating conductor so that the signal wave is sent to an external circuit such as a receiver circuit via the preamplifier circuit (see Pages 2 and 3 and FIG. 1 of Japanese Unexamined Patent Application Publication No. 5-327329, for example). That is, in the conventional electronic device of this type, the circuit board included therein is electrically connected to a pair of feed portions of the antenna radiating conductor via a lead wire or the like, and is fixed to the glass surface of the vehicle window via attachment leg pieces or the like. The connection of the electronic device to the antenna radiating conductor or the glass surface is generally made by soldering.
As in the above-described conventional technique, the electronic device, which includes therein the circuit board provided with the preamplifier circuit or the like and is attached to the glass surface of the vehicle window in the vicinity of the antenna radiating conductor, is connected to the antenna radiating conductor or the glass surface by soldering or the like to thereby secure required attachment strength. However, the electronic device has such an attachment structure that makes it extremely difficult to detach and reattach the circuit board with respect to the glass surface. Therefore, maintenance such as adjustment, repair, or component replacement of the antenna circuit including the preamplifier circuit cannot be easily performed.